A simulated decision making environment was used to test certain theoretical propositions of Schroder, Driver & Streufert (in press). It was shown that differentiation and integration in perception increases with increasing information load until a criterion of optimal perception is reached. Beyond this optimal point, differentiation and integration in perception decreases with further increasing information load. These findings may be represented as an inverted U shaped curve relating load and perception. Differences in the conceptual structure of Ss resulted in different levels of this inverted U curve. The results parallel a similar study of Streufert & Schroder (in press) concerned with differentiation and integration in performance.